Do not unnecessarily cast booleans to pointers

* cairomm/fontface.cc (USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS): Put
dummy object into an anonymous namespace and make it static.
(UserFontFace::text_to_glyphs): Do not cast a boolean to a pointer
in order to indicate state via the font face's user data.  There are
fairly safe alternative casts to do this, but it is much simpler to
just take the address of any existing object to get a non-0 pointer.
(UserFontFace::UserFontFace): Remove unnecessary casts.

2 files changed, 24 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 39bddb2..536757f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,15 @@
+2010-06-07  Daniel Elstner  <danielk@openismus.com>
+
+	Do not unnecessarily cast booleans to pointers
+
+	* cairomm/fontface.cc (USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS): Put
+	dummy object into an anonymous namespace and make it static.
+	(UserFontFace::text_to_glyphs): Do not cast a boolean to a pointer
+	in order to indicate state via the font face's user data.  There are
+	fairly safe alternative casts to do this, but it is much simpler to
+	just take the address of any existing object to get a non-0 pointer.
+	(UserFontFace::UserFontFace): Remove unnecessary casts.
+
 2009-10-26  Armin Burgmeier  <armin@arbur.net>
 
 	* MSVC_Net2005/cairomm/cairomm.rc.in:
diff --git a/cairomm/fontface.cc b/cairomm/fontface.cc
index 0ffa5c3..2071d2f 100644
--- a/cairomm/fontface.cc
+++ b/cairomm/fontface.cc
@@ -22,10 +22,15 @@
 #include <cairomm/scaledfont.h>
 #include <cairomm/private.h>
 
-namespace Cairo
+namespace
 {
 
-const cairo_user_data_key_t USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS =  {0};
+static const cairo_user_data_key_t USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS =  {0};
+
+} // anonymous namespace
+
+namespace Cairo
+{
 
 FontFace::FontFace(cairo_font_face_t* cobject, bool has_reference)
 : m_cobject(0)
@@ -306,10 +311,12 @@ UserFontFace::text_to_glyphs(const RefPtr<ScaledFont>& /*scaled_font*/,
   // negative value for the size of the glyph array, which is a special value in
   // the C API that means: "ignore this function and call unicode_to_glyph
   // instead".  If this default virtual function is ever called, it will set a
-  // bool value in the user_data, which we can read back in the
+  // non-NULL value in the user_data, which we can read back in the
   // text_to_glyphs_cb and used as a signal to return -1 for the num_glyphs
   // parameter.
-  cairo_font_face_set_user_data(cobj(), &USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS, reinterpret_cast<void*>(true), NULL);
+  // TODO: Is there a reentrancy requirement, and is this code reentrant?
+  cairo_font_face_set_user_data(cobj(), &USER_DATA_KEY_DEFAULT_TEXT_TO_GLYPHS,
+                                this, 0);
   return CAIRO_STATUS_SUCCESS;
 }
 
@@ -357,8 +364,7 @@ UserFontFace::UserFontFace()
   // store a pointer to the wrapper class in the user-data, so that when one of
   // the callback functions gets called (which has to be a plain-C function so
   // can't be a class member), we can get a reference to the wrapper class
-  cairo_font_face_set_user_data(m_cobject, &user_font_key,
-                                 (void*)this, (cairo_destroy_func_t) NULL);
+  cairo_font_face_set_user_data(m_cobject, &user_font_key, this, 0);
   cairo_user_font_face_set_init_func(cobj(), init_cb);
   cairo_user_font_face_set_render_glyph_func(cobj(), render_glyph_cb);
   cairo_user_font_face_set_unicode_to_glyph_func(cobj(), unicode_to_glyph_cb);